SECTION 1 FRESHWATER SYSTEMS UNIT 4: AQUATIC ECOLOGY

SECTION 1 FRESHWATER SYSTEMS UNIT 4: AQUATIC ECOLOGY

CENTRAL CASE STUDY: STARVING THE LOUISIANA COAST OF SEDIMENT LOUISIANA IS LOSING 25MI2 OF COASTAL WETLANDS ANNUALLY WETLANDS SUPPORT A DIVERSITY OF ANIMALS THEY ALSO PROTECT COASTAL CITIES FROM COASTAL STORMS THESE WETLANDS ARE CREATED BY SEDIMENT DEPOSITION FROM THE MISSISSIPPI RIVER SEDIMENT COMES FROM THE MISSISSIPPI S WATERSHED NATURALLY WETLANDS WOULD SINK AND DISAPPEAR WITHOUT SEDIMENT REPLENISHMENT

CENTRAL CASE STUDY: STARVING THE LOUISIANA COAST OF SEDIMENT MISSISSIPPI RIVER HAS BEEN EXTENSIVELY MODIFIED BY HUMANS OVER 2000 DAMS; DAMS SLOW WATER AND SEDIMENT DROPS OUT LEVEES ALONG THE MOUTH OF THE MISSISSIPPI SPEED UP WATER AND SHOOT SEDIMENT OUT INTO GULF OF MEXICO WITHOUT CHANGE TO THE CURRENT SYSTEM, THESE ESSENTIAL WETLANDS MAY DISAPPEAR

FRESHWATER ON EARTH FRESHWATER MAKES UP ONLY ABOUT 2.5% OF THE TOTAL WATER ON EARTH 20% - STORED IN AQUIFERS AS GROUNDWATER 1% - SURFACE WATER 79% - FROZEN IN GLACIERS AND ICE CAPS

SOME PROPERTIES OF WATER WATER IS EASILY ABLE TO ABSORB LARGE AMOUNTS OF HEAT THEREFORE, IT HAS A HIGH SPECIFIC HEAT CAPACITY BUFFERS AQUATIC ORGANISMS FROM TEMPERATURE SHOCK WATER IS CONSIDERED THE UNIVERSAL SOLVENT THIS MEANS MANY THINGS CAN DISSOLVE IN IT MAKES IT EASY TO POLLUTE WATER EXPANDS AS IT FREEZES ICE IS LARGER AND LESS DENSE THAN LIQUID WATER

THE PH SCALE THE PH SCALE QUANTIFIES THE ACIDITY OF SOLUTIONS RANGES FROM 0 TO 14 ACIDIC SOLUTIONS: PH < 7 BASIC SOLUTIONS: PH > 7 NEUTRAL SOLUTIONS: PH = 7 THE PH SCALE IS LOGARITHMIC A SUBSTANCE WITH PH OF 6 CONTAINS 10 TIMES AS MANY HYDROGEN IONS AS A SUBSTANCE WITH PH OF 7

SURFACE WATER AS WATER FLOWS OVER LAND, IT CONVERGES IN LOW-LYING AREAS THIS FORMS FLOWING OR STANDING BODIES OF WATER FLOWING RIVERS AND STREAMS STANDING PONDS, LAKES, AND WETLANDS

Flowing Surface Water

FLOWING SURFACE WATER RIVERS AND STREAMS ARE FED BY AN AREA OF LAND WHERE WATER RUNS INTO THEM THIS IS THEIR WATERSHED (DRAINAGE BASIN) AREAS SURROUNDING RIVERS AND STREAMS CAN PERIODICALLY BE FLOODED THIS AREA IS CALLED THE FLOODPLAIN AND THE SOIL HERE IS GENERALLY VERY FERTILE AT THE BEGINNING OF A RIVER OR STREAM, WATER IS CLEAR, COOL, AND FULL OF O2 (in the mountains usually) TOWARDS THE END OF THE RIVER, WATER IS SLOWER-MOVING, WARMER, LESS OXYGENATED, AND HAS HIGHER LEVELS OF ALGAE AND BACTERIA

Standing Surface Water

STANDING SURFACE WATER PONDS AND LAKES BODIES OF OPEN, STANDING WATER; LARGE LAKES ARE KNOWN AS INLAND SEAS (GREAT LAKES, CASPIAN SEA, ETC.) ZONES OF A POND OR LAKE LITTORAL AREA ON THE EDGES OF THE BODY OF WATER; HABITAT FOR ROOTED AQUATIC PLANTS BENTHIC ENTIRE BOTTOM OF THE BODY OF WATER; HABITAT FOR MANY INVERTEBRATES; NUTRIENTS SUPPLIED FROM DETRITUS (DEAD MATTER) LIMNETIC OPEN PORTION OF LAKE/POND WHERE SUNLIGHT ALLOWS PHOTOSYNTHESIS FROM PHYTOPLANKTON; SUPPORTS O2 PRODUCTION AND ZOOPLANKTON POPULATIONS PROFUNDAL WATER WHERE SUNLIGHT DOES NOT PENETRATE; LOW O2 = FEW ANIMALS

STANDING SURFACE WATER WETLANDS CAN OCCUR IN THE FORM OF FRESHWATER MARSHES, SWAMPS, BOGS, OR VERNAL POOLS WET LAND = LAND THAT IS SATURATED WITH WATER VALUABLE ECOSYSTEM SERVICES SLOW RUNOFF TO OCEAN REDUCE FLOODING RECHARGE AQUIFERS FILTER POLLUTANTS HOST MIGRATORY BIRDS

HUMAN EFFECTS ON WETLANDS HUMANS DRAIN WETLANDS FOR AGRICULTURAL LAND CANADA AND US = LOST OVER ½ OF ALL WETLANDS WE ALSO DRAIN FOR FRESHWATER AND INTRODUCE POLLUTANTS

INTRODUCED POLLUTANTS CAN AFFECT D.O. D.O. = DISSOLVED OXYGEN; AQUATIC ORGANISMS RELY ON DISSOLVED OXYGEN FOR SURVIVAL (PRIMARILY FISH) BIOLOGICAL OXYGEN DEMAND (BOD) WHEN A BODY OF WATER UNDERGOES EUTROPHICATION OR CULTURAL EUTROPHICATION (HUMAN INDUCED), D.O. PLUMMETS DUE TO INCREASE IN ORGANIC WASTE (bacteria use it to break down waste) D.O. IS ALSO NATURALLY LOW IN DEEPER PARTS OF STANDING WATER BODIES TURBIDITY DESCRIBES THE AMOUNT OF SEDIMENT PRESENT IN THE WATER; AFFECTS LIGHT TRANSMITTANCE

Thermal Stratification

THERMAL STRATIFICATION IN STANDING WATER (PRIMARILY TEMPERATE ZONE LAKES - SEASONAL TEMPERATURE CHANGE), WATER CAN SEPARATE INTO LAYERS BASED ON TEMPERATURE DURING CERTAIN TIMES OF THE YEAR, THESE LAYERS OVERTURN, MIXING D.O. AND NUTRIENTS THROUGHOUT THE LAKE

THERMAL STRATIFICATION DURING THE SUMMER, LAKES BECOME STRATIFIED INTO DIFFERENT TEMPERATURE LAYERS THAT RESIST MIXING BECAUSE SUMMER SUNLIGHT WARMS SURFACE WATERS, MAKING THEM LESS DENSE THERMOCLINE ACTS AS A BARRIER TO MIXING OF TWO LAYERS

THERMAL STRATIFICATION MIXING IN THE FALL AND SPRING WHEN TEMPERATURES CHANGE FOR SURFACE WATER, ITS DENSITY CHANGES AND IT SINKS OR RISES, CREATING THE OVERTURNING OF NUTRIENTS AND D.O. FROM THE SURFACE